Some conventional rotary machines are equipped with a stator, a rotor, and a magnetic bearing for supporting without contact the rotation of the rotor with respect to the stator. In order to avoid any direct contact between the stator and the rotor in case of failure, shutdown or overload of the magnetic bearing, which may lead, in the worst case, to the destruction of the machine when rotating at high speed, an auxiliary rolling bearing is arranged on the stator and a landing sleeve is arranged on the rotor. Upon landing of the rotor that is to say of the auxiliary rolling bearing onto the landing sleeve, the rolling bearing complements or substitutes for a short period of time the magnetic bearing in order to continue to support the rotation of the rotor with respect to the stator.
The rolling elements of the auxiliary rolling bearing are usually balls because they offer a higher possible rotational speed than rollers, but unfortunately also a lower load capacity for the auxiliary bearing.
JP-563-198451-A discloses an auxiliary bearing in the form of a thrust ball bearing onto which is fixed an elastic buffering plate to absorb the shock created by the fall of a vertical rotor upon failure of the magnetic bearing supporting the rotor.
However, in some applications, the rotary machine may be subject to much higher shocks created in the environment of the rotary machine, such as a handling shock or a military shock, resulting in too high compression forces on the balls and possibly the partial or total destruction of the auxiliary bearing, if not of the rotary machine itself, when the above mentioned patent would not prevent contact and damage to unwanted part inside the machine.
Consequently, there is room for improvement.